1. Field of the Invention
Malto-oligosaccharides, also referred to as maltodextrins and dextrose syrup solids, are produced from starch by hydrolysis with .alpha.-amylases. These carbohydrates are used in adhesives and in food applications such as syrups, flavor encapsulation, texture control, binding agents, carriers for low-calorie sweeteners, and gels in reduced-calorie foods. This invention relates to the production of novel malto-oligosaccharide compositions that contain a large proportion of maltohexaose.
2. Description of the Prior Art
Thermally stable .alpha.-amylases have enabled a rapid advance in the commercial production of malto-oligosaccharides by enzymatic hydrolysis of starch. However, the mode of the amylase action on starches in only partly understood because the fine structure of starches is still obscure. Furthermore, amylases from different sources behave differently, and their action patterns are dependent on reaction conditions. Certain amylases are now known to yield distinctive patterns of malto-oligosaccharide products that are at variance with the distribution of products that would be predicted on the basis of random cleavage of starch molecules. Robyt et al. [Arch. Biochem. Biophys. 100: 451-467 (1963)] teach that .alpha.-amylase from Bacillus subtilis selectively forms maltotriose and maltohexaose. Nakakuki et al. [Carbohydr. Res. 128: 297-310 (1984)] report that the .alpha.-amylase from B. licheniformis degrades short-chain amylose at 1% concentration and 40.degree. C. to give mainly maltopentaose and maltotriose with slightly smaller quantities of maltose. In contrast, Inglett [J. Food Biochem. 11: 249-258 (1987)] shows that this same enzyme, acting on higher substrate concentrations (20-30% starch) and at a higher temperature (95.degree. C.), yields increased quantities of maltose, essentially equivalent to or slightly higher than the other two oligomers. Slomin'ska et al. [Starch/Starke 38(6): 205-210 (1986)] show that a 72-hr saccharification of liquified starch with a thermostable maltogenic amylase from B. stearothermophilus virtually eliminates the maltohexaose (G6) constituent. Outrup et al. [Starch/Starke 36(12): 405-411 (1984) shows that treatment of amylopectin with a B. stearothermophilus amylase produces only traces of maltohexaose (G6).